Elevator-brake.



PATENTED MAR. 13, 1906.

J. E. BOYCE. ELEVATOR BRAKE. APPLICATION FILED JAN. 11, 1905;

I! l-llllilllllllulllll INVENTOR WITNESSES:

UNITED STATES PATENT OFFICE.

JOHN E. BOYCE, OF NEW YORK, N. Y., ASSIGNOR TO OTIS ELEVATOR Specification of Letters Patent.

NEW JERSEY, A CORPORATION OF ELEVATOR-BRAKE.

Patented March 13, 1906.

Application filed January 11,1905. Serial No 240,604. a

To (1,17 whmn, it may concern: I Be it known that I, JOHN E. BOYCE, a citizen of the United States, residing at New York city, in the county of New-York and State of New York, have invented certain new and useful Improvements in Elevator- Brakes, of which the following is a specification.

My invention relates to electric brakes, and has for its object to provide a brake which is automatically operated so as to produce a gentle or powerful braking efi'ect according to circumstances and which also under the direct control of the operator.

In the accompanying drawing I show my invention as applied to an electric-elevator system. The heavy lines designate the main or motor circuits, the light lines the operating and shunt-field circuits, and the broken lines designate the brake-circuits.

designates main line switch which connects the systen'i th the source of supply designated by and 1 1 is a magnet, which may be energized by a coil 12.

13, 14, 15, and 16 are poles of the magnetdircctly under which are movable armatures carrying contacts 17, 18, 19, and 20, which are so arranged that when acted upon by the ma net 1] they will be pulled up against and maize contact with the poles 13, 14, 15, and 16, respectively. These movable contacts may be located at different distances from the contact-poles 13, 14, 15, and 16 in order that as the strength of the magnet increases it will pull up the pivoted armaturcs at different times, so that if the starting resistance is connected to them, as shown, it may be short-circuitcd in successive steps. The negative main may be connected to one side ol this starting resistance by a wire 26 and the other side to the armature 61 of a motor 60 by a wire 27 through .a rcvcrsiiig-switch which will now be described. The coils 30 and 42 are adapted when energized to raise their respective cores or plungcrs 31 and 43,

' and 41.

which carry insulated contact-platcs 32 and 3t) and 44 and 53, respectively. When the plunger 31 is in the position shown in the drawing, the contact-plate 32 bridges the stationary contacts 34 and 35 and the contactplate 39 connects the stationary contacts 40 In a similar manner the contactplates 44 and 53 connect the stationary contacts 48 49 and 54 55, respectively. Upon 5 the energization of the coil or solenoid 30 its core or plunger 31 and'the plates 32 and 39, secured to it are lifted until the said plates electrically connect the contacts 29 33 28 and 36 37 38, re, ectively. In a similar manner when the p unger 43 is lifted and its contact-plate 44 establishes an electrical connection between thecontacts 46 47 and at the same time its contactlate 53 connects the-contacts 52 51. etween the contacts 35 and 48 a comparatively low resisttor-armature in a local circuit when the mo tor is being brought to rest.

It will be seen by tracing the various circuits through these two magnetically-operatcd switches that when the core 31 is raised certain circuits are closed and current will ilow through the motor-armature in one di rection and that when the core 43 is raised current will flow through the motor-armature in the opposite direction, so that this constitutes a reversing-switch by which the direction of rotation of the armature may be controlled.

represents a motor, 59 its shunt-field, and 61 its armature. i

62 and 63 are the brushes which rest on the commutator 64.

70 is a magnet connected across the brushes 62 and 63 of the motor-armature by the wires 67 and 68 66,respectively. This magnet is provided with a plunger 72, which carries at its lower end the insulated contactplate 75. This contact-plate normally connects the stationary contacts 73 and 74 togethpr that is, when the coil 71 is not energize the contacts 73 and 74, and this is short-circuited when the plate 75 connects the contacts 73 and 74. To the right of the magnet are shoivn limit-switches, which are intended to be opened when the car reaches the upper or lower limits of its travel. They comprise pivoted arms 77, v80, 83, and. 86.

A resistance 76 is connected across,

1036 311118 11011112! 7 (301M100 6 0011 810 S 'n lly t a t t 78 I lenoid 93, plunger 92, and pole-piece 91. To

the lower end of this plunger 92 is fastened a rod 95, on which slides a contact-plate 97,

-two stationary contacts 98 and'99.

which is insulated from the rod by the insulation 101. 96 is a stop-pin which limits the downward movement of the contact-plate 97 on the rod 95. 94 is a compression-spring surrounding a portion of the rod 95, and 100 is the brake-shoe, which is adapted to engage with some revolving partof the elevator machinery. It may be applied in the usual way by means of a sprin or weight. Directly under the contact-p ate 97 are shown These contacts are electrically connected by the contact-plate 97 when the plunger 92 is in the position shown in the drawings that is, when the bralreis applied to stop the motion of the elevator machinery. V

200 designates a manually-operable control-switch which way be located in the elevator-car.

201 is the operating-handle; 202 a lever pivoted at 203 and carrying the contacticce 205, which is insulated from the lever oy means of the insulation 204. \Vhen the handle 201 is moved from its central position to the left or right, the contact-piece 205 bridges the stationary contacts 206, 207, and 208 or 209, 210, and 211.

213 designates a switch in which the stationary contacts 214' and 215 are normally connected by the contact-plate 218, but which maybe arranged to break the circuit between these contacts whenever the hoisting-cable becomes slack.

The operation of this device is as follows: if the operator inove'the lever 202 to the right, the movable contact 205 will bridge the fixed contacts 209 and 210, and a circuit will be established between the negative main 26, through the wire 217 and slack-cable switch 213, wire 212, contact-piece 205, wire 219, through the brake-coil 93, from here by wire 220 to the contact 73, through contact-plate to cont-act 7 by wire 221 to contact99, contact-plate 97, contact 98, through the resistance 89 to contact 87, from there to contacts 88 84, and by wire 222 to the positive main 223. Thus a circuit has been established from the positive main to the negative main, including the brake-magnet 93 and resistance 89. This resistance 89 is so proportioned that it limits the current in the brake-coil. to an amount that is just sufhcient to slightly-ease off the brake,but is not enough to raise the brake-shoe suificiently to allow the elevator mechanism to start in 1110-- tionthat is, the brake is still applied, but not with its full ower. Now if the operator move the handle 201 to its extreme right hand position the contact-piece 205 will bridge the contacts 209, 210, and 211. Ourrent will now flow from the positive main through wires 223 224, the limit-switches 77 and 80, wire 226, contacts 54 55, and contact-plate 53, wire 225, solenoid 30, wire 224, contact 211, co'ntactpiece 205, contact 209,

wire 212, slack-table switch 213, and wires 217 26 to the negative main. This operation will excite the magnet 30, which will draw its plunger 31 upwardly until the lower contact-plate 39 bridges the three contacts 36, 37, and 38. The contact 36 is connected to the positive main by the wire 223, so that current new {lows from wire 223 to contact 36, contact 37, wire 220, to the brake-mag net 93. This last operation short-circuits the resistance 89, so that the brake-magnet will receive current at the full potential of the supply. .lt then raises the brake-shoe 100 and lifts the engagement-plate 97 out of contact with the contacts 98 and 99. When the magnet 30 raises its plunger 31, as has been described, the contact-plates 39 and32 connect the contactsflG 37 38 and contacts 29, 33, and 28, respectively. Circuits will thus be closed through the motor, and it will tend to revolve in a certain direction. The starting-resistance is arranged to be cut out automatically by the nmgnet 11, which is shown connected in a well-known manner. When the contact-plate 39 is raised, it breaks the connection between the contacts 40 and 41 and opens the circuit to the coil 42 through the wire 230, thus preventing the magnet coils 30 and 42 from being both energized at the same time. In a similar manner when the plunger 43 is up the circuitto magnetcoil 30 and wire 225 is broken at the contacts 54 55. The shunt-field 59 of the motor may be connected across the mains by the wires 69 and 227. Should the operator move the operatingdever 202 to the left, the system would go through the same operations, ex cept that in this case the coil 42 would be excited and the plunger 43 raised. The contact-plates and 53 W uld be raised, so that they would bridge their respective contacts 46, 45, and 47 and 52, 50, and 51,-respectively. This would establish such circuits through the motor that it would revolve in the opposite direction. The solenoid 71 is connected in shunt to the motor-armature,

so that when the reversing-switch last open ated is restored to its nornral position and the motor is acting as a generator it shall be suiliciently energized to lift its plunger 72 and throw the resistance 76 in series with the brake-magnet solenoid 93. When the motor slows down-to a predetermined speed, the plunger 72 is dropped and the resistance 76 short-circuited by the contact-plate 75, c0- acting with the contacts 73 and 7 4. I In order to stop the elevator, the operator moves the lever. 202 back until the contact 211 is uncovered. The contact piece 205 bridges the contacts 208', 209, and 210. This operation breaks the circuit to the magnet 30, so thatit becomes deenergized and allows the plunger 31 to drop until the contactplates 32 and 39 bridge the contacts 34 35 and 40 41, respectively. This breaks the circuit of the magnet 11 which denergizes it and allows the "contacts 17, 18, 19, and to drop back to their original position, which is shown on. the drawing, so that the starting resistance is again inserted in the armaturecircuit ready for the next start.

When the plunger 31 drops, the'contact 37 is disconnected from the contact 36 and main line 228, so that the circuit through the wire 220 to the braken'iagnet is opened. The brake-magnet is at once denergized and its plunger 92 drops until the contact-plate 97 bridges the contacts 98 and 99. A circuit is thereby reestablished through the bra kemagne't, as current will now How to the same by wire 222 through resistance 89 and 76.

The magnet 70, as already described, is connected. across the armature-terminals and depends for its operation on the potential of the revolving motor-armature. As its plunger 72 is raised during the usual running of the motor the contact-plate 75 is lifted from contacts 73 and 74 and the resistance 76 is inserted. between the wires 22 1 and 220. it has alr'e ly been shown that when the reversing-switch plungers 31 and 43 are down and the contacts 37 and 50, respectively, are disconnected from the positive main 223 the brakennagnct cannot get its supply of eurrent from the positive mam by wire 220. it must, tlmrcfore, got it through the wire 222. As the circuit through the brake-magnet now includes the resistances 89 and 76, the brake coil )3 will receive but little current and the brake will be applied with considerable force. As soon, however, as the motor-armature has slowed down a predetermined amount the potential across its brushes and the strength of the magnet 7 will no longer be sufficient to hold its plunger 72 up. The latter will then short'circuit the resistance 76. This will allow more current to flow through the brake-magnet and will ease oil thebrake slightly---just 'suflicient to allow the car to come to rest without jar. If the resistance 56 is used, it is connected in a local circuit in series with the n'iotor-armature 64 when both of the plungers 31 and 43 are down. While the armature is rotating the current which it generates flows through this resistance 56, thus producing a load on the motor which acts as an clectrodynamic brake which tends to bring the motor to rest. T he limit-switch arms 77 and 80 are to automatically open the circuits of the reversing-switch coils and 42 as the car approaches the limit of its travel. Should they operate, the current would be cut oil from the motor and the circuit to the brakcnnagnet would be opened either at the contact- 37 or the contact 50.

.This would allow the brake to be applied cirhuiting the brake-magnet 93 and applying the brake with maximum force. Should the slack-cable switch 213 operate to open the circuit connected to the controlling-switch 200, all current would be cut oil from the brake, and it would be applied with full ow'er.

' It will be seen from the foregoing that in all ordinary cases by placing the operating. switch 200 in its intermediate position the car will be brought to rest gently, and for all ordinary stops I prefer to do this way. Should, however, the operator desire to apply the brake with its full power, he may bring the operatin -switch 200 to its central position. As the current. to the brake-magnet always flows through the wire 219, its cricuit would thereby be broken at contact 210 or 207 and the magnet 93 would be to tally denergized, so that the brakeshoe 100 would be applied with its full power.

When my invention is used, a heavier or stronger brake may be employed than is usual in systems of this. character. it will ease itsell' oi'l' automatically if applied in the usual way, so that the mechanism to which it is applied may be brought to rest gently, or it may be applied with full force at once, thus providing an emergency brake. As these operations are entirely under the controlol' the operator and is he may apply the brake under all conditions, even if other parts of the apparatus fail to work, its advantages are obvious. tures is that by combining it with automatic limit-stops it will prevent another class of accidents which are caused by the driven mechanism overrunniug its prescribed limits of movement...

My invention is applicable to other mechanisms than electric elevators, and-I do not wish to limit myself to that particular use, as I described it merely to exemplify some of the advantages of thcinvcntion.

Instead of the magnet controlling a. resistance, 76 in one step, as shown, it may be arranged to cut out or short-circuit a series of resistances succcssively in some such way, i or example, as is illustratedin connection with magnet 11 on the drawing.

\Vhat'i clairnis-- 1. The combination with an electric motor, of a brake therefor, and manually-oontrolled means for applying the brake with full/power or with diflerent degrees of power depending upon the speed of the motor.

2. The combination with an clectricmotor, of an electric brake, and means ionautomatic- I ally easing ofi' the brake as the'motor'comes to rest. p v V 3. The combination with an electric motor, of a brake therefor, an electromagnet arranged to release said brake, and automatic tor for varyin e current in such magnet.

'4. The com ination with an electric'motor,

Another of its valuable lea-- means dependin upon the speed of the m'B- I of a brake therefor, an electromagnet arranged to release said brake, a resistance in series with said ma net, and means depending upon the speed of the motor for automatically short-circuiting the resistance.

5. The combination with an electric motor, of a brake therefor, an e ectromagnet arranged to release said brake, a resistance for said magnet, a source of electrical supply, manually-operable means for connecting said magnet directly to the source of electrical supply or connecting the magnet to the source of supply through the resistance, and means depending upon the speed of the motor for automatically short circuiting' such resistance.

6. The combination with an electric motor, of' a brake therefor, an electromagnet arranged to release said brake, resistances adapted to be connected in series with said magnet, a source of electrical supply, manually-operable means for connecting the mag net directly to the source of electrical supply or for connecting the magnet to the source of electrical supply through said resistances, and means depending upon the speed'of the motor for short circuiting part of said resistances.

7. The combination with an electric motor, of a brake therefor, an electromagnet arranged to release said brake, resistances adapted to be connected in series with said magnet, a source of electrical supply, manually-operable means for connecting the magnet directly to the source of electrical supply or for connecting the magnet to the source of electrical supply through said resistances, automatic means for cutting off all current which flows to the magnet except that which 40 flows through said resistances, and means de' ally-operable means for connecting the magnet directly to the source of electrical supp or for connecting the magnet to the source of electrical supply through said resistances, automatic means for cutting off the current which flows to the magnet except that which flows through said resistances, means depending upon the speed of the motor for shortcircuiting part of said resistances, and additional automatic means for cutting off all current from the magnet.

9. The combination with an electric motor, of a brake therefor, an electromagnet arranged to release said brake, resistances adapted to be connected in series with said magnet, a source of'electrical supply, manually-operable means for connecting the ma not directly to the source of electrical supply or for connecting the-magnet to the source of electrical supply through said resistances, automatic means for cutting off the current from said magnet except that which flows through the resistances, means depending upon the speed of the motor for short-circuiting one of said resistances, additional automatic means for cutting off all current from said magnet. In witness whereof I have signed my name in the presence of two subscribing witnesses.

JOHN E. BOYCE.

Witnesses \V. H. BRADY, WALTER C. STRANG. 

